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JS/js/prdtoa.c  view on Meta::CPAN

		word0(db) += (k >> 2)*Exp_msk1;
		if (k &= 3)
			db *= 1 << k;
	}
#else
	if (k > 0)
		word0(da) += k*Exp_msk1;
	else {
		k = -k;
		word0(db) += k*Exp_msk1;
	}
#endif
	return da / db;
}

static CONST double
tens[] = {
	1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9,
	1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19,
	1e20, 1e21, 1e22
#ifdef VAX
	, 1e23, 1e24
#endif
};

static CONST double
#ifdef IEEE_Arith
bigtens[] = { 1e16, 1e32, 1e64, 1e128, 1e256 };
static CONST double tinytens[] = { 1e-16, 1e-32, 1e-64, 1e-128, 1e-256 };
#define n_bigtens 5
#else
#ifdef IBM
bigtens[] = { 1e16, 1e32, 1e64 };
static CONST double tinytens[] = { 1e-16, 1e-32, 1e-64 };
#define n_bigtens 3
#else
bigtens[] = { 1e16, 1e32 };
static CONST double tinytens[] = { 1e-16, 1e-32 };
#define n_bigtens 2
#endif
#endif

#ifdef JS_THREADSAFE
static PRBool initialized = PR_FALSE;

/* hacked replica of nspr _PR_InitDtoa */
static void InitDtoa(void)
{
	freelist_lock = PR_NewLock();
        p5s_lock = PR_NewLock();
	initialized = PR_TRUE;
}
#endif


/* nspr2 watcom bug ifdef omitted */

PR_PUBLIC_API(double)
PR_strtod(CONST char *s00, char **se)
{
	int32 bb2, bb5, bbe, bd2, bd5, bbbits, bs2, c, dsign,
		e, e1, esign, i, j, k, nd, nd0, nf, nz, nz0, sign;
	CONST char *s, *s0, *s1;
	double aadj, aadj1, adj, rv, rv0;
	Long L;
	ULong y, z;
	Bigint *bb, *bb1, *bd, *bd0, *bs, *delta;

#ifdef JS_THREADSAFE
	if (!initialized) InitDtoa();
#endif

	sign = nz0 = nz = 0;
	rv = 0.;
	for(s = s00;;s++) switch(*s) {
	case '-':
		sign = 1;
		/* no break */
	case '+':
		if (*++s)
			goto break2;
		/* no break */
	case 0:
		s = s00;
		goto ret;
	case '\t':
	case '\n':
	case '\v':
	case '\f':
	case '\r':
	case ' ':
		continue;
	default:
		goto break2;
	}
break2:
	if (*s == '0') {
		nz0 = 1;
		while(*++s == '0') ;
		if (!*s)
			goto ret;
	}
	s0 = s;
	y = z = 0;
	for(nd = nf = 0; (c = *s) >= '0' && c <= '9'; nd++, s++)
		if (nd < 9)
			y = 10*y + c - '0';
		else if (nd < 16)
			z = 10*z + c - '0';
	nd0 = nd;
	if (c == '.') {
		c = *++s;
		if (!nd) {
			for(; c == '0'; c = *++s)
				nz++;
			if (c > '0' && c <= '9') {
				s0 = s;
				nf += nz;
				nz = 0;
				goto have_dig;
			}

JS/js/prdtoa.c  view on Meta::CPAN

	bd0 = s2b(s0, nd0, nd, y);

	for(;;) {
		bd = Balloc(bd0->k);
		Bcopy(bd, bd0);
		bb = d2b(rv, &bbe, &bbbits);	/* rv = bb * 2^bbe */
		bs = i2b(1);

		if (e >= 0) {
			bb2 = bb5 = 0;
			bd2 = bd5 = e;
		}
		else {
			bb2 = bb5 = -e;
			bd2 = bd5 = 0;
		}
		if (bbe >= 0)
			bb2 += bbe;
		else
			bd2 -= bbe;
		bs2 = bb2;
#ifdef Sudden_Underflow
#ifdef IBM
		j = 1 + 4*P - 3 - bbbits + ((bbe + bbbits - 1) & 3);
#else
		j = P + 1 - bbbits;
#endif
#else
		i = bbe + bbbits - 1;	/* logb(rv) */
		if (i < Emin)	/* denormal */
			j = bbe + (P-Emin);
		else
			j = P + 1 - bbbits;
#endif
		bb2 += j;
		bd2 += j;
		i = bb2 < bd2 ? bb2 : bd2;
		if (i > bs2)
			i = bs2;
		if (i > 0) {
			bb2 -= i;
			bd2 -= i;
			bs2 -= i;
		}
		if (bb5 > 0) {
			bs = pow5mult(bs, bb5);
			bb1 = mult(bs, bb);
			Bfree(bb);
			bb = bb1;
		}
		if (bb2 > 0)
			bb = lshift(bb, bb2);
		if (bd5 > 0)
			bd = pow5mult(bd, bd5);
		if (bd2 > 0)
			bd = lshift(bd, bd2);
		if (bs2 > 0)
			bs = lshift(bs, bs2);
		delta = diff(bb, bd);
		dsign = delta->sign;
		delta->sign = 0;
		i = cmp(delta, bs);
		if (i < 0) {
			/* Error is less than half an ulp -- check for
			 * special case of mantissa a power of two.
			 */
			if (dsign || word1(rv) || word0(rv) & Bndry_mask)
				break;
			delta = lshift(delta,Log2P);
			if (cmp(delta, bs) > 0)
				goto drop_down;
			break;
		}
		if (i == 0) {
			/* exactly half-way between */
			if (dsign) {
				if ((word0(rv) & Bndry_mask1) == Bndry_mask1
					&&  word1(rv) == 0xffffffff) {
					/*boundary case -- increment exponent*/
					word0(rv) = (word0(rv) & Exp_mask)
						+ Exp_msk1
#ifdef IBM
						| Exp_msk1 >> 4
#endif
						;
					word1(rv) = 0;
					break;
				}
			}
			else if (!(word0(rv) & Bndry_mask) && !word1(rv)) {
			drop_down:
				/* boundary case -- decrement exponent */
#ifdef Sudden_Underflow
				L = word0(rv) & Exp_mask;
#ifdef IBM
				if (L <  Exp_msk1)
#else
					if (L <= Exp_msk1)
#endif
						goto undfl;
				L -= Exp_msk1;
#else
				L = (word0(rv) & Exp_mask) - Exp_msk1;
#endif
				word0(rv) = L | Bndry_mask1;
				word1(rv) = 0xffffffff;
#ifdef IBM
				goto cont;
#else
				break;
#endif
			}
#ifndef ROUND_BIASED
			if (!(word1(rv) & LSB))
				break;
#endif
			if (dsign)
				rv += ulp(rv);
#ifndef ROUND_BIASED
			else {
				rv -= ulp(rv);
#ifndef Sudden_Underflow
				if (!rv)
					goto undfl;
#endif
			}
#endif
			break;
		}
		if ((aadj = ratio(delta, bs)) <= 2.) {
			if (dsign)
				aadj = aadj1 = 1.;
			else if (word1(rv) || word0(rv) & Bndry_mask) {
#ifndef Sudden_Underflow
				if (word1(rv) == Tiny1 && !word0(rv))
					goto undfl;
#endif
				aadj = 1.;
				aadj1 = -1.;
			}
			else {
				/* special case -- power of FLT_RADIX to be */
				/* rounded down... */

				if (aadj < 2./FLT_RADIX)
					aadj = 1./FLT_RADIX;
				else
					aadj *= 0.5;
				aadj1 = -aadj;
			}
		}
		else {
			aadj *= 0.5;
			aadj1 = dsign ? aadj : -aadj;
#ifdef Check_FLT_ROUNDS
			switch(FLT_ROUNDS) {
			case 2: /* towards +infinity */
				aadj1 -= 0.5;
				break;
			case 0: /* towards 0 */
			case 3: /* towards -infinity */
				aadj1 += 0.5;
			}
#else
			if (FLT_ROUNDS == 0)
				aadj1 += 0.5;
#endif
		}
		y = word0(rv) & Exp_mask;

		/* Check for overflow */

		if (y == Exp_msk1*(DBL_MAX_EXP+Bias-1)) {
			rv0 = rv;
			word0(rv) -= P*Exp_msk1;
			adj = aadj1 * ulp(rv);
			rv += adj;
			if ((word0(rv) & Exp_mask) >=
				Exp_msk1*(DBL_MAX_EXP+Bias-P)) {
				if (word0(rv0) == Big0 && word1(rv0) == Big1)
					goto ovfl;
				word0(rv) = Big0;
				word1(rv) = Big1;
				goto cont;
			}
			else
				word0(rv) += P*Exp_msk1;
		}
		else {
#ifdef Sudden_Underflow
			if ((word0(rv) & Exp_mask) <= P*Exp_msk1) {
				rv0 = rv;
				word0(rv) += P*Exp_msk1;
				adj = aadj1 * ulp(rv);
				rv += adj;
#ifdef IBM
				if ((word0(rv) & Exp_mask) <  P*Exp_msk1)
#else
					if ((word0(rv) & Exp_mask) <= P*Exp_msk1)
#endif
						{
							if (word0(rv0) == Tiny0
								&& word1(rv0) == Tiny1)
								goto undfl;
							word0(rv) = Tiny0;
							word1(rv) = Tiny1;
							goto cont;
						}
					else
						word0(rv) -= P*Exp_msk1;
			}
			else {
				adj = aadj1 * ulp(rv);
				rv += adj;
			}
#else
			/* Compute adj so that the IEEE rounding rules will
			 * correctly round rv + adj in some half-way cases.
			 * If rv * ulp(rv) is denormalized (i.e.,
			 * y <= (P-1)*Exp_msk1), we must adjust aadj to avoid
			 * trouble from bits lost to denormalization;
			 * example: 1.2e-307 .
			 */
			if (y <= (P-1)*Exp_msk1 && aadj >= 1.) {
				aadj1 = (double)(int32)(aadj + 0.5);
				if (!dsign)
					aadj1 = -aadj1;
			}
			adj = aadj1 * ulp(rv);
			rv += adj;
#endif
		}
		z = word0(rv) & Exp_mask;
		if (y == z) {
			/* Can we stop now? */
			L = (Long)aadj;
			aadj -= L;
			/* The tolerances below are conservative. */
			if (dsign || word1(rv) || word0(rv) & Bndry_mask) {
				if (aadj < .4999999 || aadj > .5000001)
					break;
			}
			else if (aadj < .4999999/FLT_RADIX)
				break;
		}
	cont:
		Bfree(bb);
		Bfree(bd);
		Bfree(bs);
		Bfree(delta);
	}
retfree:
	Bfree(bb);
	Bfree(bd);
	Bfree(bs);
	Bfree(bd0);
	Bfree(delta);
ret:
	if (se)
		*se = (char *)s;
	return sign ? -rv : rv;
}

static int32
quorem(Bigint *b, Bigint *S)
{
	int32 n;
	Long borrow, y;
	ULong carry, q, ys;
	ULong *bx, *bxe, *sx, *sxe;
#ifdef Pack_32
	Long z;
	ULong si, zs;
#endif

	n = S->wds;
#ifdef DEBUG
	/*debug*/ if (b->wds > n)
		/*debug*/	Bug("oversize b in quorem");
#endif
	if (b->wds < n)
		return 0;
	sx = S->x;
	sxe = sx + --n;
	bx = b->x;
	bxe = bx + n;
	q = *bxe / (*sxe + 1);	/* ensure q <= true quotient */
#ifdef DEBUG
	/*debug*/ if (q > 9)
		/*debug*/	Bug("oversized quotient in quorem");
#endif
	if (q) {
		borrow = 0;
		carry = 0;
		do {
#ifdef Pack_32
			si = *sx++;
			ys = (si & 0xffff) * q + carry;
			zs = (si >> 16) * q + (ys >> 16);